The field of this invention is vessel connectors.
Pin-type vessel closure connectors are known in the art. For example, U.S. Pat. No. 3,780,90l of this inventor discloses a pin-type vessel closure connector for connecting a vessel head or closure to a vessel shell or cylinder. The connector includes an annular yoke formed of double concentric rings separated by an annular recess. The annular yoke is attached to either the vessel head or the vessel shell. A single annular connector ring or finger is mounted on the other vessel section for insertion into the annular recess between the double connector rings. A plurality of pins are insertable into radially aligned openings in the connector rings for the purpose of releasably connecting the vessel head and vessel shell together.
In U.S. Pat. No. 3,372,828, wherein the present inventor is a co-inventor, it is noted that tapered pins have certain advantages over straight cylindrical pins when used as vessel connectors. For example, tapered pins are more easily inserted into the aligned openings since the forward, smaller end of the tapered pin acts as a wedge to finally align the openings between the vessel sections as the pin is inserted. Tapered pins are also easier to remove. However, time and expense are necessary to accurately machine the exact, radially aligned, tapered openings in the double connector rings and the single connector ring for receiving the tapered pin.
Another difficulty with pin-type connectors is found in actual field installation of the single connector ring into the annular recess between the double connector rings. Although the circumference of the single connector ring is predesigned to properly and easily fit into the annular recess between the double connector rings, manufacturing tolerances and field handling may cause a discrepancy in the circumference of the single connector ring which would cause problems with fitting the single connector ring into the annular recess between the double connector rings. Also, installation of the vessel section containing or having the double connector rings, which generally includes the steps of mounting the vessel section in concrete and welding it in place, may cause some variation in the circumference or roundness of the double connector rings and the annular recess therebetween. For these reasons, it is necessary to somehow compensate for changes in the circumference or roundness of either the single connector ring or the double connector rings. One possible solution is to provide for a generous clearance between the single connector ring when positioned in the annular recess between the double connector rings. However, this clearance allows for greater relative movement, during temperature expansion and contraction, between the single connector ring and double connector rings, thereby enhancing the "racheting" effect which tends to push the pins out of position.